Waveguide and method of manufacture

Abstract

A hollow waveguide ( 1 ) has a wall ( 3 ) having plural pegs ( 16 ) thereon. The pegs ( 16 ) which project into the hollow interior of the waveguide ( 1 ) such that the waveguide ( 1 ) propagates electromagnetic waves only below a certain frequency. The surface of each of the pegs ( 16 ) is substantially free of discontinuity and concavities. The waveguide ( 1 ) may be manufactured by a moulding process.

1. A hollow waveguide, the waveguide comprising a wall having plural pegs thereon which project into the hollow interior of the waveguide such that the waveguide propagates electromagnetic waves only below a certain frequency, the surface of each of the pegs being substantially free of discontinuity and wherein at least some of the pegs have a substantially elliptical cross-sectional shape. 
   
   
     2. A wave guide according to  claim 1 , wherein the surface of each the pegs is substantially free of concavities. 
   
   
     3. A waveguide according to  claim 1 , wherein at least some of the pegs have a substantially circular cross-sectional shape. 
   
   
     4. The hollow waveguide of  claim 1 , wherein each of the plural pegs has a convex head. 
   
   
     5. A waveguide according to  claim 1 , wherein the waveguide is dimensioned to propagate only electromagnetic waves having a frequency less than about 100 GHz. 
   
   
     6. A waveguide according to  claim 1 , wherein at least some of the pegs have a domed head. 
   
   
     7. A waveguide according to  claim 1 , wherein at least one peg has a convex fillet around its base at the junction between the peg and the wall. 
   
   
     8. A waveguide according to  claim 1 , comprising a second wall opposing the first wall and spaced therefrom, the face of the second wall that opposes the first wall being substantially planar. 
   
   
     9. A waveguide according to  claim 1 , wherein the waveguide is dimensioned to propagate electromagnetic waves having a frequency of at least 10 GHz. 
   
   
     10. Transmitter-receiver apparatus, the apparatus comprising:
 at least one antenna for transmitting and receiving signals, 
 an electronics module for providing signals to the antenna for transmission and for receiving signals received by the antenna, and 
 a hollow waveguide selectively coupling the electronics module to the antenna, the waveguide having a wall having plural pegs thereon which project into the hollow interior of the waveguide such that the waveguide propagates electromagnetic waves only below a certain frequency, the surface of each of the pegs being substantially free of discontinuity and wherein at least some of the pegs have a substantially elliptical cross-sectional shape.